Something that is becoming a real headache for sites like mine that display recent referers is referer spam. This is where a site, mostly porn sites, appears as a referer to yours, but if you check the site they don't actually link to you. The purpose of this is to increase their
Google PageRank - the fake referer appears as a link, and the greater the number of links, the higher a page will be in a Google search.
The way that they are doing this is by having a list of targets and then generating a dynamic page on their site that uses a meta refresh tag to redirect to their next 'victim'. It would not be difficult for them to write a script that continually displays this page in a browser, thus generating thousands of fake referals.
There is no easy way to stop this whilst still allowing genuine referals through.
b2evolution, the software that I use, has a function that blocks refers from a blacklist. A similar result is achieved by using a .htaccess file if your web server supports them. If you already have a file named .htaccess in the root of your site append the following to the bottom, else copy the following to a text editor, save it as .htaccess (including the leading .) and ftp it to your server. Replace domain.com and domain2.com with the domains you want to ban and add similar lines until you have included all sites that spam you.
RewriteEngine On #this line should only appear once in .htaccess
RewriteCond %{HTTP_REFERER} ^http://(www.)?domain.com(/)?.*$ [OR]
RewriteCond %{HTTP_REFERER} ^http://(www.)?domain2.com(/)?.*$ [OR]
RewriteRule .* - [F,L]
Be warned, this is not a permanent solution as new spammers seem to appear every couple of days, but it will allow you to keep your referers section relatively clean if you keep it updated.
There may be ways to crash the spammer's browser using this method. One that I'm going to try over the next couple of days is redirecting to a page that then uses javascript to try and get the browser in to a loop (window.location.history.go(-2) or infinite popups maybe?). I'll keep you posted.